Wolff, Robert Lee
Garland Publishing, 1981
Buku Referensi
compiled by Robert Lee Wolff
Garland Publishing, 1984
Buku Referensi
Karl, Frederick R.
Farrar, Straus and Giroux, 1964
Buku Teks SO
Ludlum, Robert
Grafton, 1991
Buku Teks SO
Brownings, Robert
Everymans Library, 1964
Buku Teks SO